High-power and high-energy stability injection lock laser light source for double exposure or double patterning ArF immersion lithography

ArF immersion technology is spotlighted as the enabling technology for below 45nm node. Recently, double exposure technology is also considered for below 32nm node. We have already released an injection lock ArF excimer laser with ultra-line narrowed and stabilized spectrum performance: GT61A (60W/6kHz/ 10mJ/0.35pm) to ArF immersion market in Q4 2006. The requirements are: i) higher power ii) lower cost of downtime for higher throughput iii) greater wavelength stability for improved overlay and iv) increased lifetimes for lower operation costs. We have developed high power and high energy stability injection lock ArF excimer laser for double patterning: GT62A (90W/6000Hz/15mJ/0.35pm) based on the technology of GT61A and the reliability of GigaTwin (GT) platform. A high power operation of 90W is realized by development of high durability optical elements. Durability of the new optics is at least 3 times as long as that of the conventional optics used in the GT61A. The energy stability is improved more than 1.5 times of performance in the GT61A by optimizing laser operational conditions of the power oscillator. This improvement is accomplished by extracting potential efficiency of injection lock characteristic. The lifetime of power oscillator, which is one of the major parts in cost of ownership, is maintained by using higher output of the power supply.